What’s New in BJ?

What’s New in Biophysical Journal?

Emerging Biophysical Technologies

Have you noticed the new Emerging Biophysical Technologies (EBT) featured papers on the Biophysical Journal website as part of each issue? As an initiative to highlight physics-based methods, editors are selecting papers to be featured and writing a short description about why this new method is important. Here are some of the latest featured EBT papers. To view the papers, visit www.biophysj.org.

It is clear that mechanical properties of cells and the forces impinging on a cell translate into biochemical changes. These are typicallycharacterized for a whole cell or a population of cells. Shekhar et al. have constructed a novel probe/perturbant, a magnetic particle coupled to a fluorescent sensor of local chemistry. With this, they simultaneously characterize the rheology of a small volume of cytoplasm and the changes in the pH of an internalized vesicle (phagosome) as it trafficks into the cell interior. The probe lets them go beyond characterization, to show that perturbing the centripetal movement of a phagosome changes the kinetics of its acidification. As the authors note, the method has many applications to cell biophysics. Indeed, their probe may well be the prototype for a number of such probes able to perturb subcellular processes, for example by local heating rather than by mechanical force.

Frequency-modulated Kelvin probe force microscopy (FM-KPFM) is a relatively new technique for mapping the local electrostatic surface potential simultaneously with AFM topography images with superior resolution and sensitivity (few nm and few 10 mV). Previously developed KPFM methods have limited application in biological research, while FM-KPFM has proven to be advantageous for studying the surface potential maps in complex self-assembled biological samples on surfaces such as supported model and biological membranes.

FCS, a powerful technique for measuring diffusion and other protein motions within cells, readily resolves multiple species within a population, but at the cost of sampling only a single spot. The authors develop a technique, multiconfocal fluorescence correlation spectroscopy (mFCS), for measuring the diffusion and binding dynamics of heat-shock protein in five spots simultaneously with a time resolution of 14 μs. The improved method promises to be a general method for resolving spatial heterogeneities in protein-protein interactions within a living cell.

The Biophysical Society was founded in 1958 to encourage development and dissemination of knowledge in biophysics. It does so through its many programs, including its meetings, publications, and committee outreach activities.